1. Field of the Invention
The disclosed embodiments of the present invention relate to a communication system.
2. Description of the Prior Art
In conventional communication systems, the transmitter designs decide related transmission configurations, including the modulation and coding scheme (MCS), the spatial stream number, the transmission power level, etc., based on the channel quality, so as to achieve the best utilization of the channel bandwidth.
A transmitter based communication device is usually utilized for acting as a data transmission interface in a system, and connected to a host via a Host Control Interface (HCI). Indifferent applications, communication devices may employ host control interfaces which are designed based on different specifications. For instance, in a notebook application, the communication device may employ the Peripheral Component Interconnect Express (PCI-E) based host control interface for communicating with the host. In a smart phone application, the communication device may employ the Secure Digital Input/Output (SDIO) based host control interface for communicating with the host. In addition, if the communication device is an interface for connecting external devices, the communication device may employ the Universal Serial Bus (USB) based host control interfaces for communicating with the host. Therefore, the conventional communication device usually possesses host control interfaces complying with multiple specifications.
Due to diversity of the host control interface, compatibility has to be taken into consideration at the design phase of communication devices. For example, a communication device with a USB 3.0 based host control interface is required to identify host's connection interfaces complying with different USB versions such as USB 1.1, 2.0, and 3.0, or identify host's connection interfaces complying with the USB specification and the PCI-E specification. However, the interface specifications of host's different connection interfaces have different power consumption limits. For instance, in the USB 2.0 specification, the permitted power consumption is under 2.5 W for peripherals; however, in the USB 3.0 specification, the permitted power consumption is under 4.5 W. That is to say, a communication device which communicates with a host through a USB 2.0 based host control interface has a power consumption limit of 2.5 W, while a communication device which communicates with a host through a USB 3.0 based host control interface has a power consumption limit of 4.5 W.
As can be readily known from the foregoing, due to diversity of the host control interface, there has to be a mechanism implemented in the communication device to configure various transmission settings by simultaneously referring to different specifications of host control interfaces and the channel quality.